I recently updated our pioreactors to the latest software version and hence the od dodging setup in the config.ini changed to the version below (lets call it target_rpm_od_dodging):
However, when I test target_rpm_od_dodging the stirring bars go out of balance all the time regardless of having different values for during and outside values.
I remember also tested the target_rpm_od_dodging setup when it came out for the first time and encountered the same issue. Because of that I went back to the older version and kept that until we updated our pioreactors to v1.5. Considering all this information, I would like to ask:
Is it possible to test the previous od dodging setup in the most recent software version?
Is the way target_rpm_od_dodging works different than previous way where the stirring was just pausing and starting? (e.g., fan is kept active/passive during the pause).
Is there a specific reason to have target_rpm_outside_od_reading ? In our case, this option is redundant as we want the reactors to have the same initial_target_rpm outside the dodging event.
Also if there is any data I can provide that can make the troubleshooting easier, please feel free to request.
Yes, I am sorry for not being elaborate! I am refering to 25.5.22 where the config.ini for stirring is as:
[stirring.config]
target_rpm=800
initial_duty_cycle=50
pwm_hz=300
use_rpm=1
duration_between_updates_seconds=23
post_delay_duration=1.00
pre_delay_duration=1.00
# if turning enable_dodging_od on, we recommend decreasing samples_per_second to at most 0.10
enable_dodging_od=True
I’ll look into this tomorrow, but can you explain more what you mean by “out of balance”? Also, do you have an active stirring calibration on the Pioreactor(s)?
Good hint! The previous trials had stirring calibration but the last trials did not have that. I will test it today.
We are using cross-shaped stirring bar and when it goes “out of balance” it is one of the two cases below:
The bar stops rotating. Instead, it just vibrates at a fixed position.
The bar rotates in a way that the bar makes a circle rotation around the vial which it hits to the walls of the vial to give some noise.
Case 2 is not problematic as most of the time the bar keeps stirring. We are experiencing case 1. I can provide a short clip of the case for further elaboration in case needed.
The issue is solved after the stirring calibration was defined. Thank you for all the help!
During testing I realized that the vials were floating slightly above the heating pad, which was the other contributor for the “out of balance” situation. The o-ring in some reactor setups made it difficult to put the vial into the chamber so I had to apply force from the top, and did not realize that the vials were not all the way down. However, this happened in 2 out of the 3 reactors I am testing.
I do not think this is an issue and I am noting this here only for other users to check their vial if they experience resistance.